Safety device for presses.



R. B. BENJAMIN SAFETY DEVICE FOR PRESSES.

APPLICATION FILED APR.25, 1913.

I 1,212,176, Patented Jan. 16,1917.

f'zgU UNITED STATES, PATENT OFFICE.

REUBEN B. BENJAMIN, OF CHICAGO, ILLINOIS, ASSIGNOR TO BENJAMIN ELECTRICMANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SAFETY DEVICE IEOR PRESSES.

Specification of Letters Patent.

PatentedJan. 16, 1917.

Application filed Apri125, 1913. Serial N 0. 763,577.

provements in Safety Devices for Presses,

of which the following is a full, clear, concise, and exact description,reference being had to the accompanying drawing, forming a part of thisspecification.

y invention relates to improvements in safety manipulating devices forintermittently operated machinery, and particularly for intermittentlyoperating punch presses and the like.

One of the objects'of my invention is to provide a mechanism which willinsure the.

operators hands being in a place of safety .when the-machinery is causedto operate.

In my co-pending application, filed April 25, 1913, Serial No. 763,576,I haveshown my invention embodied in one form, in which the variousparts are operated entirely by electricity. In the present embodiment Ihave illustrated some of the parts as being mechanically operated.

For the purpose of disclosing my invention, I have illustrated the sameapplied to a-punch press in the accompanying drawings.

A In said drawings Figure'l is a side elevation of suflicient of a punchpress to illustrate the application of my invention; and

Fig. 2 is a front elevation of a portion of a punch press, showing indetail a certain part of my invention as applied thereto.

I In. said drawings, the machine .1 is a punch press having the usualframe 2 and a trip mechanism by means of which the clutch between thepunch and source of power is thrown into, driving connection. The triping mechanism'may be of any of the well En tion of.v the same istherefore not'required here, except to state that after the clutch hasbeen once thrown and has caused the punch to descend the clutch willautomatically be disconnected.- This tripping mechanism is operated, byan electro-magnet 4, which is connected to the movable member 3 of thetripping mechanism by a connecting rod 5. The circuit of thiselectro-magnet,

which is included in the wires 6,7, 8 and 9, has interposed at one pointa switch 10,

which is adapted to be held closed by a movown constructions, and adescrip-- 'lower end of the solenoid core. The downward movement of thisswitch arm permits the spring arms of switch 10 to open, thereby openingthe circuit of the electro-magnet after it has operated to trip thepress. A sliding stop 13 held in its normal or projected position by aspring 14, engages over the top of the switch arm 11 after it has beenushed down, and prevents the arm from eing raised until the propermechanism is operated to move the stop 13 out of the-path of the switcharm and permit the switch arm to again rise under the influence of thespring 12. This operating mechanism consists of a latch 15 adapted toengage the rear end of the stop 13. This latch is provided at its rearend with a rocking arm 16 pivoted at its center to the latch and havingone end thereof connected by a link 17 with a 'rockin arm 18 looselymounted on the shaft 26. T e opposite end of the arm 18 is connected bya suitable link 19 with a slidable hand band 21. This hand band is suported from the top of the frame by afsuitaiile resilient support in theform of a spring 22 onne ted at its upper end by bolt 23 with thetopportion of the frame. The opposite end of the arm 16 is connected by alink 24 with an arm 25 mounted on the end of a shaft 26 extending acrossthe front portion of the press frame.

this sha t is provided with an arm 27 which The opposite end of in turnis connected by the link 28 with a slidable hand connector 29 supportedby a coiled spring 30 in a manner similar to the connector 21. 'Asuitable stop 31 is arranged to prevent the arm 18 from being rocked toofar rearward. In addition to the switch 10 in the circuit of theelectro-magnet 4, a second switch 32 is arranged in this circuit, whichswitch is normally opened but the contacts of which are in a position tobe closed by the forward movement of the end of the latch 15. It will benoted that-a lateral movement and vertical movement of these connectorsis permissible in addition to their forward movement, which forward andrearward movement carries with it the operating arms 25 and 18. By thisarrangement the connectors, which are adapted to be fastened to thehands of the operator, permit a free movement of the hands of theoperator and at the same time provide a means for causing the trippingof the press under certain predetermined conditions.

In operation, we will assume that the parts are in the positionillustrated in the drawings, and that the operator has placed a suitablepiece of material in the press to be operated upon. The operator thendraws both hands backward out of the danger zone of the press. When theoperator draws both hands back, the left hand will cause the shaft 26 torotate, throwing forward the arm 25 and therefore giving a forwardtendency to the upperend of the rocker arm 16. At the same time, themoving back of the right hand will throw rearward the upper end of thearm 18, which will cause the lower end of the arm 16 to move forward.This will move the latch 15 forward, thereby causing the spring contactsof the switch 32 to close, and thereby closing the circuit through theelectro-magnet 4:, causing it to pull down on the movable member 3 andtrip the press. As soon as the electro-magnet trips the press theextension on the lower end of its core will move the switch arm 11downwardly, thereby permitting the spring arms of the switch 10 to open.The front end of this switch arm 11 will be caught beneath the end ofthe stop 13 and the arm will be prevented from again returning to closethe switch under the influence of the spring 12. The operator now takesup one of the pieces of material, his hand being in a natural po-.

sition for doing this, and holding one hand stationary, he moves theother hand forward, or he may move both hands forward if desired. Ineither case, the forward movement of one or both hands will cause a rearwardmbvement of the latch 15, which latch will pull back the stop 13 sothat the switch arm 11 may be moved up to close the switch 10. At thesame time, this rearward movement of the arm 15 will cause the switch 32to open so that the circuit through the electro-magnet will again beopen at this point. It will now be seen that the circuit cannot again beclosed until both hands are moved rearwardly and out of the zone ofdanger. This is due to the fact that if one hand, say the left hand, ismoved rearward while the right hand is maintained in a position ofdanger, the arm 16 will merely rock on its pivot and will not move thelatch 15 sufficiently forward to close the switch 32. Likewise, if theright hand is moved rearward the arm 16 will merely rock on its pivotand will not sufficiently move the latch 15. Therefore, it will be seenthat both arms must be moved rearward in order to close the switch 32.

Having thus described my invention, what tro-magnet, mechanical meansfor resetting said switch controlled by either of two members movablewith the operators hand, and a second switch in the electro-magnetcircuit controlled by said members and arranged to be closed when bothhands of the operator are out of the zone of danger.

2. In a device of the character described, the combination with amovable member for tripping the clutch of a press, of an electromagnetfor operating said movable member, a switch for controlling the circuitof said electro-magnet, mechanical means for closing said switch,hand-manipulated devices operating said means, said means beinginoperative for closing the circuit of the electro-magnet when thehand-manipulated devices are individually operated, and operative forclosing the circuit of the electromagnet when the hand-manipulateddevices are operated collectively and when both hands of the operatorare out of the zone of danger.

3. In a device of the character described, the combination with amovable member for controlling the clutch of a press, of anelectro-magnet for operating said movable member, a switch opened by themovement of said electro-magnet, a movable member for causing saidswitch to be closed, a latch for operating the same, mechanism foroperating the latch movable with the hands of the operator and operablefor moving said movable member when either hand is moved toward themechanism of the press, and a second switch closed by said mechanism,said mechanism being only operable to close the switch when both handsof the operator are moved out of the zone of danger.

4:. In a device of the character described, the combination with amovable member, of an electro-magnet for operating said movable member,a switch opened by the ,movement of said electro-magnet, a slidable stopfor controlling the restoring of the switch, means for operating saidstop to permit a restoring of the switch, a second switch controlled bysaid means, a pair of movable members movable with the hands of theoperator, and interdependent connections between the movable members andthe slidable member for operating said slidable member to permit therestoration of the first switch upon the movement of either of the pairof movable members when the hands are moved toward the press and forclosing the second switch only when both hands of the-operator are movedout of the zone of danger.

5. In a device of the character described, the combination with amovable member for tripping the clutch of a press, of an electromagnetfor operating said movable member, a switch opened by saidelectro-magnet, an arm controlling the opening and closing of saidswitch, means tending to move said arm to close the switch after it hasbeen once opened, a stop moved into the path of the switch when the sameis opened, means for moving the stop out of the path of the switch, asecond switch, a rocker arm centrally pivoted on said means, a movablemember moving with one hand of the operator connected to one end of saidrocker arm, a. movable member moving with the other hand of the operatorconnected to the other end of said rocker arm, the connection being suchthat when one hand is moved toward the mechanism of the press theswitch-controlling arm will restore the switch to closed position andwhen both hands are moved out of the zone of danger the second switchwill be closed to cause the operation of said electro-magnet.

6. In a device of the character described, a machine having a tool whichmoves in a definite path, electromagnetic means -for controlling theoperation of said tool, and means for controlling the operation of saidelectromagnetic means, comprising a movable member, a rocker armpivotedto said member intermediate the ends of the arm, manuallycontrolled means connected to one end of said rocker arm for actuatingit, and manually controlled means movable independently of saidfirst-named manually controlled means connected to the other end of therocker arm.

7. In a device of the character described, a machine having a toolmovable in a definite path, electromagnetic means for controlling theoperation of said tool, a switch for controlling said electromagneticmeans,

to an intermediate means for controlling said switch comprising amovable member, a rocker arm pivoted to said member, intermediate theends of the arm, manually controlled means connected to one end of saidrocker arm for actuating it, and manually controlled means movableindependently-of said first-named manually controlled means connected tothe other end of the rocker arm.

8. In a device of the character described a machine having a partmovable in a definite path, electromagnetic means for controlling theoperation of said part, and means for controlling the operation of saidelectromagnetic means comprising a movable member, two independentlymovable manually controlled means for acting on said member to move it,and means for so restricting the movement of said manually controlledmeans that both must be oper-' ated to move said member sufliciently tocause the electromagnetic means to operate.

9. The combination with a hand feed machine having a part movable in adefinite path for operating on material, of means whereby the movementof either hand ofthe operator to a position adjacent the path of saidpart will prevent movement of said part, and whereby movement of bothhands of the operator to a posltion away from the path of said part Wlllcause movement of said part, said means including a member constructedso that it is moved to one position when both hands of the operator areadjacent said path, and so it'is moved to another position when bothhands of the operator are withdrawn, and so it is moved position whenone hand only is withdrawn.

In witness whereof, I have hereunto subscribed my name in the presenceof two witnesses.

' REUBEN B. BENJAMIN. WVitnesses:

J. PERRY HALEY, ANNE SOLOMON.

